(Invited) Unraveling Synergistic Interactions driving the Chemical Mechanical Planarization Process

Abstract

Due to the emergence of sub-10 nm technologies, next generation CMP slurry formulations have continued to increase in additive (nanoparticle and chemistry) complexity to meet stringent device specifications. Therefore, it is essential to probe the molecular level interactions at the nanoparticle/slurry chemistry/substrate interface and in turn correlate them to key performance metrics such as removal rate, post CMP defects, planarization efficiency. More specifically, this work has developed a suite of techniques that explore the adsorption/complexation dynamics that evolve during the CMP process. Employing a suite of techniques such as modified atomic force microscopy (AFM), electrochemical quartz crystal nanobalance (EQCN), dynamic contact angle measurements, fluorescence microscopy, pre/post polish characterization of particle properties (size and zeta potential), and in-situ rotating disk electrode open circuit potential measurement the critical static and dynamic mechanisms can be exposed. Correlation of this information gives way to modulation (desired or undesired) of the CMP performance potentially providing tunabilty (process and formulation) at advanced technology nodes to meet stringent electrical, topography, and defect requirements. Furthermore, these methods have shown great promise as a vehicle to probe the molecular level interactions at the nanoparticle/chemistry/ substrate interface. Results have shown excellent correlation to key process performance metrics and have provided insight into relevant surface chemistry changes that impact critical interactions during the CMP process. This presentation will address key interactions through a series of case studies focusing on probing the impact of inhibitor structure on the substrate surface energy relevant to Cu CMP, the role of slurry chemistry on controlling defectivity during STI post-CMP cleaning, and effect of organic additives on the modulation of nanoparticle surface properties to enhance STI CMP performance.